Powder Coating Over Silicon Bronze Weldment

Hi.

Anyone familiar with powdercoating of steels knows that silicon is a " toxin " to the powdercoating process.

It causes contamination of the process line , causes lack of adhesion of the powder coating and is very difficult to eliminate once any of it creeps in to the plant.

We have an item that must be welded with Silicon Bronze weld metal using MIG due to the thin 0.7 mm zinc plated sheet metal and requirement for minimal distortion .

We cant use TIG process with steel filler rod because the time and costs would blow out too much , and MIG process with steel wire ( ER70- S4 ) cant be used because it blows holes through the sheetmetal and reacts poorly with the zinc plating , whereas Silicon bronze tolerates the zinc plating and wont blow holes through the joint , although it requires lowest minimum settings on an pulse MIG inverter welder with stepless arc voltage adjustment ( arc volts average setting is 14.6 volts )

I am looking for opinions on how to gaurantee we wont contaminate the powdercoat line using this weld metal.

The welding wire has 3.4 % silicon , but most of it burns off during welding , there is a small amount of silicon scale residue on the weld surface which is ground off before plating.

The welding and grinding process is carried out at another location.

Can anyone advise how much if any silicon would remain in the weld metal ?

Are there any solvents we can use before coating that would dissolve any remaining silicon present on the surface ?

We have carried out coating of some small weld samples and found them to coat well with no pitting , but we have heard of another site where this process was carried out where they had contamination of the coating line and couldnt determine if the silicon bronze was to blame ( or if a neighboring business had caused contamination from overspray by painting their factory roof at the same time )

anyone got experience with the above and can share opinions please ?